Psykologien bak et finanskollaps

What happens when the market starts to tank? The initial response is dismissal, for the investor still believes that his stocks will come back up and there is no point in selling.

As prices slip further, denial cedes to fear and then, suddenly, to panic.

Traumatised by their loss, investors vow never to invest in stocks again — a sentiment that can be durably enforced if many others have also been burned.

A famous example of this process was «Tulip Mania», which occurred in the 17th-century Netherlands. Tulip bulbs, then a rarity in Europe, scaled extraordinary heights in the course of a mad year, only to fall just as abruptly.

At the Mania’s peak in 1636, a single bulb of a particularly coveted strain, the Viceroy tulip, changed hands for the equivalent of more than 25,500 euros (36,720 dollars) today. When the bubble burst, there was a wave of moralising and calls for tighter controls against speculators.

Trond Andresen, who specialises in behavioural analysis at the Norwegian University of Science and Technology, says investors may think less about the intrinsic value of a stock and more about the perception of its value.